数组“映射”

Question

If I have an array of items, for example:

var names = ['Rita', 'Sarah', 'Lisa', 'Joe', 'Ralph', 'Linda', 'Richard', 'Chris'];

And I have an array of numbers, for example:

var numbers = [2, 3, 5, 7];

How would I use these numbers to act as order numbers to get specific names?

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What I mean by that?

Have a function that takes those two arrays and gives me an output:

output = ['Lisa', 'Joe', 'Linda', 'Chris'];

Does JavaScript have any specific functions for that or would I need to code something myself?

Answer 1

Use map() for that

 var names = ['Sarah', 'Lisa', 'Joe', 'Ralph', 'Linda', 'Richard', 'Chris']; var numbers = [2, 3, 5, 7]; var res = numbers.map(function(v) { return names[v - 1] }) // with ES6 arrow function // var res = numbers.map(v => names[v - 1]); document.write('<pre>' + JSON.stringify(res, null, 3) + '</pre>'); 

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Or using filter()

 var names = ['Sarah', 'Lisa', 'Joe', 'Ralph', 'Linda', 'Richard', 'Chris']; var numbers = [2, 3, 5, 7]; var res = names.filter(function(v, i) { return numbers.indexOf(i + 1) > -1; }) // with ES6 arrow function // var res = numbers.filter((v, i) => numbers.indexOf(i + 1) > -1); document.write('<pre>' + JSON.stringify(res, null, 3) + '</pre>');